Variable valve train for a cam activated lifting valve of an internal combustion engine

Abstract

The invention relates to a variable valve train ( ) for a cam-actuated lifting valve ( ) of an internal combustion engine, which valve ( ) is loaded by a closing spring ( ) acting against the direction of opening, with an approximately cylindrical force application element ( ) located between a cam ( ) and the valve ( ), whose length can be adjusted hydraulically and whose exterior cylindrical wall face ( ) is slidable in a fixed guide cylinder ( ), said element ( ) being provided with a pressure piston ( ) longitudinally slidable in a cylinder ( ), which piston ( ) is adjacent to a pressure chamber ( ) into which opens a pressure channel ( ) departing from a port ( ) in the wall face ( ) of the force application element ( ), a fixed pressure line ( ) opening into the guide cylinder ( ) in the area of the port ( ), which line ( ) can be subjected to hydraulic high pressure (p ) permitting hydraulic activation of the valve ( ). In order to obtain a variable valve train ( ) independet of crank angle (KW) in as simple a manner as possible, a permanent flow connection is provided between pressure line ( ) and pressure channel ( ) independently of the position of the force application element ( ).